1. Field of the Invention
The present invention relates to an IC card radio modem usable in combination with a plurality of infrastructure-compatible units and a communication system using this modem and, more particularly, to an IC card radio modem which accommodates a plurality of connectable infrastructure-compatible units in a single dedicated package (modem main body) to realize communication with an infrastructure network which is arbitrarily selected from an IC card unit side, and a communication system using this modem.
2. Description of the Prior Art
A conventional IC card radio modem of this type has a structure in which an IC card unit and an infrastructure-compatible unit compatible with a single infrastructure network form a pair (set) inside or outside the card, as disclosed in, e.g., Japanese Unexamined Patent Publication No. 2-268390.
In the above-described conventional IC card radio modem, the IC card main body and the infrastructure-compatible unit are paired. For this reason, if a system unit accommodating and using an IC card radio modem performs communication through a different network, the IC card radio modem must be exchanged for one corresponding to the type of the infrastructure network for communication. Therefore, the conventional IC card radio modem cannot cope with a requirement for communication with an arbitrary infrastructure network in accordance with command control or the like from the system unit.
The present invention has been made in consideration of the above situation in the prior art, and has as its object to provide an IC card radio modem which allows data communication with one infrastructure arbitrarily selected from a plurality of infrastructures by using the IC card radio modem in the same system unit without exchanging the IC card, and a communication system using this modem.
In order to achieve the above object, according to the first aspect of the present invention, there is provided an IC card radio modem comprising an IC card unit storing infrastructure type information in a memory, a plurality of infrastructure-compatible units connected to the IC card unit at multiple points through an IC card interface, and an antenna for sending information to a designated external infrastructure.
According to the second aspect of the present invention, there is provided an IC card radio modem wherein the plurality of infrastructure-compatible units according to the first aspect are accommodated in a modem main body incorporating the antenna and having a slot for receiving the IC card unit.
The IC card unit according to any one of the first and second aspects is constituted by a PCMCIA interface, an IC card controller, connected to the PCMCIA interface, for controlling an entire IC card, the memory connected to the IC card controller, and an infrastructure-compatible interface connected to the IC card controller. In addition, each of the plurality of infrastructure-compatible units is constituted by an IC card interface connected to the IC card unit and connection-controlled by predetermined control procedures, an infrastructure-compatible controller connected to the IC card interface, and an infrastructure network-compatible interface connected to the infrastructure-compatible unit.
According to the third aspect of the present invention, there is provided a communication system using an IC card radio modem, comprising an IC card unit storing infrastructure type information in a memory, a system unit, connected to the IC card unit through an interface having an interface function based on a PCMCIA standard, for inputting a command related to a start of data communication and designation of a to-be-used infrastructure, and a plurality of infrastructure-compatible units connected to the IC card unit at multiple points through an IC card interface, wherein communication through an arbitrary infrastructure-compatible unit selected from the IC card unit side is allowed.
According to the fourth aspect of the present invention, there is provided a communication system wherein the plurality of infrastructure-compatible units according to the third aspect are accommodated in a modem main body incorporating the antenna and having a slot for receiving the IC card unit.
The IC card unit according to any one of the third and fourth aspects is constituted by a PCMCIA interface, an IC card controller, connected to the PCMCIA interface, for controlling an entire IC card, the memory connected to the IC card controller, and an infrastructure-compatible interface connected to the IC card controller. In addition, each of the plurality of infrastructure-compatible units is constituted by an IC card interface connected to the IC card unit and connection-controlled by predetermined control procedures, an infrastructure-compatible controller connected to the IC card interface, and an infrastructure network-compatible interface connected to the infrastructure-compatible unit.
As described above, the IC card radio modem of the present invention has an IC card unit accommodated in a system unit and a plurality of infrastructure-compatible units corresponding to different infrastructure network as a radio modem. The infrastructure-compatible unit to be used for data communication can be switched in accordance with to-be-used infrastructure designation information from the system unit without exchanging the IC card which has been mounted in the system unit, thereby smoothly performing data communication through a radio channel.
The above and many other advantages, features and additional objects of the present invention will become manifest to those versed in the art upon making reference to the following detailed description and accompanying drawings in which preferred structural embodiments incorporating the principles of the present invention are shown by way of illustrative example.